Vermont’s three-man congressional delegation faces a difficult choice in deciding whether to support a resolution authorizing President Obama to strike at Syria after the most recent poison gas attack by the government against the Syrian people.

Sens. Patrick Leahy and Bernard Sanders and Rep. Peter Welch are all appropriately wary of the commitment of U.S. forces to another war in the Middle East. Like most Vermonters, they remember the fakery and lies of the George W. Bush administration, which perpetrated one of the great foreign-policy blunders of the nation’s history in Iraq.

It is true as well that military action always leads to unintended consequences. Ten years after our invasion, Iraq may be coming apart at the seams, rather than serving as a model of democracy in the heart of the Arab world. Who knows what an attack on Syria might provoke Iran to do? An attack against an Arab regime, even for good reasons, is likely to provoke resentment in the Arab world, despite support from the klatch of monarchies whom we count as allies.

The instincts of Leahy, Sanders and Welch might well be to vote no to a new engagement in the Middle East. Who appointed the United States the police officer of the world? It’s a question that has been asked throughout the past century. In the face of that question, we have often found reasons to assume the police role despite isolationist tendencies that wax and wane over time.

And yet doing nothing is also a choice with consequences. So far the Obama administration has for good reasons chosen a policy of restraint in relation to the Syrian civil war. We have learned that it is delusional to believe we can shoot our way into town and rearrange Arab societies to our liking. As the world has watched, the Syrian war has claimed more than 100,000 lives, and millions have become refugees. President Obama has not waded in so far because it has not been clear what he might do that wouldn’t make things worse.

It is worth noting the differences between Syria and Iraq. In Iraq, Saddam Hussein was a murderous tyrant who in the past had gassed his own people, with the United States looking the other way. But at the time of our invasion, he was not threatening anyone. There was no war. We created the war.

In Syria, civil war is well under way, and lately President Bashar al-Assad has taken it to another level by unleashing poison gas. As Thomas Friedman has pointed out in a column, international norms have outlawed the use of poison gas, and yet the international bodies that might enforce those norms are paralyzed. To do nothing in response to Assad’s use of poison gas is for humanity to adopt a policy of — whatever.

A policy of whatever would embolden other vicious leaders to believe they can act with impunity in using weapons of mass destruction. The world has embraced norms that outlaw genocide and certain undiscriminating weapons. We enforce those norms only haltingly, but here is an instance where action in response is appropriate.

Choosing an appropriate strategy will be important. Our strategy ought to be designed to dovetail with the needs of the secular, anti-radical rebels who are locked in competition with al-Qaida-allied Islamists. We can’t sort out the complex tangle of Syria’s war, but we can show Assad and others that they must pay a price if they use weapons of mass destruction.

Obama has adopted a clever political ploy in asking for Congress’ approval, dividing Republicans, some of whom were willing to wage war because of weapons of mass destruction that didn’t exist but hesitate when those weapons have actually been used. The Democrats were already divided.

Leahy, Sanders and Welch may well be standing against the opinion of a majority of Vermonters if they support Obama’s resolution. But not doing so may be to initiate a policy of fatal passivity that would empower the most heinous leaders at the expense of the interests of humanity.